Last year I had to replace the mobo in my Dell Studio 540, Quad 4-duo, 64-bit computer, installing one that was supposed to be exactly the same. After reassembly there were no problems encountered with the OEM version of Vista rebooting. Now I want to upgrade the OS from Vista Home Premium SP2 to Windows 7 Pro. Since the mobo was identical, can I use the OEM upgrade version instead of the full version? I've read where a new mobo changes the identity of the computer as far as the Microsoft EULA is concerned, but is each mobo individually identified, or does that apply only if you upgrade/change motherboards? Based on my previous experience with rebooting Vista, I think this system is recognized as the same computer, but I don't want to buy the less expensive upgrade only to find it won't work